You can check if the BFO oscillator (the one in the tin can) is working by checking the DC voltage on test point TP4004, which is actually located outside of the tin can (not the one inside). The test and adjustment procedure is located on page 23 of the Technical Supplement. It takes a very steady hand and good tools to adjust the stock trimmer (peak the voltage on TP4004).
Note that the exact voltage levels can vary rig-to-rig, but you should see 2-7 volts at all times, and there should be a 3v or so movement as you sweep the width knob.
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-Mat Breton, N8TW
Mat Breton N8TW